This invention relates to an improved treadmill, and in particular, to manually operated apparatus for controlling the motion of the treadmill.
Typically, a treadmill is used as an exercising device to maintain physical fitness or to help rehabilitate people who have sustained injury or are recovering from an operation. Most treadmills involve an endless belt that is disposed about a series of rollers mounted within a stationary frame. A portion of the belt surface describes a "walking plane" upon which the person exercising strides or runs. Conventionally, the inclination of the walking plane may be adjusted to various positions in reference to the horizontal plane. At a relatively high angle of inclination, the exerciser is forced to exert considerably more energy than when the walking plane is in a relatively level position.
It is also important to the proper operation of the system that the exerciser can overcome the forces of friction allowing him to keep the system moving uniformly and smoothly. To this end, a flywheel arrangement is generally employed which is arranged to absorb any fluctuations in speed that might occur and thus impart a smooth motion to a person mounted upon the device.
Unfortunately, it is extremely difficult to obtain a smooth motion with a simple flywheel arrangement under all operating conditions. Situations can arise that are dangerous to the exerciser. For example, when the belt is easily movable, mounting and dismounting the treadmill can only be achieved with great difficulty. A weak or infirmed exerciser can thus lose his balance when attempting to mount or dismount the treadmill and sustain injury. Furthermore, the momentum of the system can overtake the ability of the exerciser to keep up causing a fall which, again, could prove to be harmful.